Disease repair method suitable for shear keys of operating immersed tunnel

Abstract

The invention relates to the technical field of civil engineering structure repair, and discloses a shear key disease repair method suitable for an operating immersed tunnel, which comprises the following steps: a, an evaluation step: carrying out safety evaluation on a shear key of the operating immersed tunnel to determine the damage degree of the shear key; b, substrate treatment: performing substrate treatment on the non-uniform deformation part of the immersed tunnel to improve the substrate compactness and adjust the non-uniform deformation; c, a repairing step: according to a result of the evaluation step, selecting one of the following modes to repair the shear key: c1, when the shear key structure is not damaged, repairing by adopting a reinforcing mode; and c2, when the shear key structure is damaged, the shear key structure is repaired in a replacement mode. According to the method, the horizontal shear keys of the bottom plate of the immersed tunnel are transformed into the structure capable of providing temporary vertical constraint, and the technical problem that the invalid shear keys of the side wall are safely replaced under the condition that operation traffic is not interrupted is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of civil engineering structure repair, in particular to a method for repairing shear key diseases of an operating immersed tunnel. BACKGROUND

[0002] An immersed tunnel is formed by connecting multiple prefabricated segments underwater, and is an important traffic infrastructure for crossing rivers, bays, etc. At the joints between the segments, shear keys are usually provided, which are key structures for transmitting shear forces between the segments and play a decisive role in maintaining the stability of the overall structure of the tunnel and controlling the uneven deformation between the segments.

[0003] During long-term operation, the shear keys of the immersed tunnel may be damaged due to the combined effects of various factors such as uneven settlement of the tunnel foundation, changes in external loads, and deterioration of material properties, such as concrete crushing and steel corrosion and fracture. These diseases weaken the shear force transmission capacity between the segments, causing excessive relative displacement of the joints, and thus affecting the normal use and long-term safety of the tunnel.

[0004] For the shear key diseases that have occurred in the operating immersed tunnel, some repair methods are provided in the prior art. However, these technologies still have some limitations in application. Existing repair practices often fail to form a complete technical process including disease cause diagnosis, root cause treatment, structure repair, and effect verification. Repair work is sometimes only directed at the shear key body, without addressing the external factors that cause the disease, which limits the long-term effectiveness of the repair.

[0005] In addition, when the shear key is severely damaged and needs to be replaced, safety control during construction is a technical difficulty. In particular, for the vertical shear keys of the side wall, after they are removed, the segments will temporarily lose effective vertical constraints, and without reliable temporary support measures, they are prone to misalignment under the action of vehicle load or soil pressure, posing a serious safety risk. The existing technology lacks mature and reliable solutions on how to provide a safe and efficient temporary vertical constraint for replacing the shear keys of the side wall.

[0006] At the same time, existing repair operations, especially replacement repairs involving structure removal and recasting, usually require complete interruption of tunnel traffic to provide the necessary work space and safety environment for construction. Such long-term traffic interruption will bring significant economic and time costs to society, especially for busy core channels, the impact is more pronounced. Therefore, how to complete the repair without interrupting or minimizing the impact on tunnel operation is another challenge faced by the existing technology. SUMMARY

[0007] In view of the deficiencies of the prior art, the present application provides a method for repairing shear key diseases of an operating immersed tunnel, which solves the problems of high construction safety risk and complete traffic interruption in the prior art when repairing the shear key of the immersed tunnel.

[0008] To achieve the above object, the present application is implemented by the following technical solutions: a method for repairing shear key diseases of an operating immersed tunnel, comprising the following steps:

[0009] a. an evaluation step of evaluating the safety of the shear key of the operating immersed tunnel to determine the damage degree thereof;

[0010] b. a base treatment step of treating the part of the immersed tunnel where uneven deformation exists to improve the base density and adjust the uneven deformation;

[0011] c. a repair step of repairing the shear key according to the result of the evaluation step by selecting one of the following modes:

[0012] c1. when the shear key structure is not damaged, the reinforcing mode is used for repair;

[0013] c2. when the shear key structure is damaged, the replacement mode is used for repair, which comprises: first, transforming the original horizontal shear key of the immersed tunnel bottom plate into a temporary shear structure with both horizontal and vertical shear resistance, then replacing the vertical shear key of the side wall by using the vertical temporary constraint provided by the temporary shear structure, and finally, restoring the shear key of the bottom plate part;

[0014] d. an acceptance step of evaluating the safety of the repaired shear key to confirm the repair result.

[0015] Preferably, the evaluation step a specifically comprises:

[0016] collecting the original design data, geological data and operation monitoring data of the immersed tunnel, and conducting on-site investigation to obtain the data of base density, structural cracks, shear key damage degree and stress state; comparing the obtained data with the design deformation limit value to comprehensively evaluate the safety degree of the shear key.

[0017] Preferably, the reinforcing mode c1 is specifically to reinforce by using an Ω-shaped steel plate, which comprises:

[0018] using an Ω-shaped steel plate, and connecting the flat section of the Ω-shaped steel plate and the side wall at both ends of the immersed joint by clamping groove to provide vertical shear resistance by using the Ω-shaped steel plate.

[0019] Preferably, the width of the bending section of the omega-shaped steel plate is adapted to the spacing of the pipe joint connector joints, and the size and strength of the flat section and the side wall of the immersed pipe joint are determined according to the shear strength requirements.

[0020] Preferably, in the replacement mode c2, the original horizontal shear key of the bottom plate is transformed into a temporary shear structure in the following manner:

[0021] At the position of the original horizontal shear key of the bottom plate, a new shear key structure with a concave-convex stepped connection form is arranged, which realizes the horizontal and vertical shear transmission functions through the engagement of the upper and lower steps.

[0022] Preferably, all the demolition and construction operations in the replacement mode c2 are implemented in a block-by-block and part-by-part manner to ensure that the traffic in the tunnel is not interrupted during the repair process.

[0023] Preferably, the acceptance step d specifically includes:

[0024] The repaired shear key structure is subjected to stress monitoring, deformation monitoring and material durability testing, and is evaluated by experts. If the evaluation is unqualified, the repair step c is repeated.

[0025] The present application provides a method for repairing defects of a shear key of an immersed tunnel in operation.

[0026] Advantages:

[0027] 1. The present application divides the defect state of the shear key into two cases of structure not being damaged and structure being damaged, and respectively adopts a reinforcement mode or a replacement mode for treatment. This design avoids the blindness of repair operations, makes the selection of the technical scheme have objective basis, and at the same time, performs a base treatment step before repair, which aims to treat the external causes of the defect, thereby improving the fundamentality and effectiveness of the repair work.

[0028] 2. The present application first transforms the original horizontal shear key of the bottom plate into a temporary shear structure with a concave-convex stepped connection form, so that it can provide temporary vertical restraint capacity. On this basis, the failed side wall vertical shear key is removed and replaced. This operation sequence provides necessary structural safety redundancy for the removal of the side wall shear key, which is a high-risk link, and effectively prevents the pipe joint misalignment caused by lack of vertical restraint during the repair process.

[0029] 3. In the implementation of the present application, especially for the replacement repair method which needs to be structurally demolished and newly built, the operation mode of block and site is adopted. This construction organization mode allows the normal traffic of other lanes in the tunnel to pass while the repair operation is carried out. Therefore, the present method can complete the repair of the key load-bearing components without interrupting the overall operation function of the tunnel, thereby significantly reducing the influence of the repair project on social traffic. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a method step diagram of the present application;

[0031] Figure 2 is a shear key cross section of the original immersed tube segment of the present application;

[0032] Figure 3 is a shear key Ω-shaped steel plate reinforcement plan view of the present application;

[0033] Figure 4 is a shear key Ω-shaped steel plate reinforcement cross-sectional view of the present application;

[0034] Figure 5 is a detail structure diagram of the Ω-shaped steel plate of the present application;

[0035] Figure 6 is a detail section view of the immersed tube structure bottom plate shear key reconstruction structure of the embodiment of the present application. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the specification of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0037] Please refer to the drawings in the specification of the present application Figure 1 The embodiment of the present application provides a method for repairing shear key diseases of an operating immersed tube tunnel, which comprises the following steps:

[0038] a. Evaluation step: safety evaluation of the shear key of the operating immersed tube tunnel to determine the damage degree;

[0039] In the present embodiment, before performing the subsequent base treatment and shear key repair operation, step a is first performed, that is, the safety evaluation of the shear key of the operating immersed tube tunnel. The execution of this step provides objective technical criteria for the selection and development of the subsequent repair scheme.

[0040] The shear key safety evaluation step aims to comprehensively and accurately obtain the current technical state of the shear key and define its damage level. This step is achieved by the following means:

[0041] First, collect basic information. This work aims to establish an objective understanding of the design intent, original state, and engineering environment of the shear key by retrieving historical technical archives. The collection work includes but is not limited to:

[0042] Retrieve the original design drawings, which can specifically include the structural design drawings of the pipe section, the reinforcement layout, the detailed drawings of the shear key structure, and the material specification description. These drawings clearly show the original design load capacity and construction form of the shear key.

[0043] Retrieve the engineering geological survey report to understand the characteristics of the foundation bearing layer and hydrogeological conditions at the tunnel location, providing a basis for analyzing the causes of uneven settlement and other diseases.

[0044] Retrieve the construction plan and related records, especially those related to pipe joint construction and foundation treatment, to trace possible original construction deviations.

[0045] Collect deformation monitoring data during the years of operation, such as pipe section settlement and horizontal displacement records. By analyzing these time series data, the historical development law of structural deformation and the current deformation rate can be grasped.

[0046] After completing the collection of basic information, then perform on-site investigation and measurement of the disease site to obtain the current actual state data of the shear key and its surrounding structure. This work mainly includes:

[0047] Foundation state detection. Use non-destructive testing equipment such as ground penetrating radar to scan the bottom plate of the disease pipe section. The principle of this detection is to emit and receive high-frequency electromagnetic waves, and generate two-dimensional or three-dimensional cross-sectional images of the foundation filling layer under the tunnel bottom plate according to the characteristic differences of electromagnetic wave reflection signals in different media. According to the image, the location, range, and approximate scale of the possible void, cavity, or insufficient density area inside the foundation can be determined.

[0048] Structure state detection. This detection targets the shear key body and adjacent pipe joint concrete structure. The specific operation includes: using a crack width observation instrument and a depth measuring instrument to record and quantify the crack distribution, orientation, maximum width, and development depth of the concrete surface; the concrete strength at the disease site can be detected using the rebound method or ultrasonic method to evaluate the degree of deterioration of its load capacity; preferably, the steel reinforcement corrosion potential detection method can be used to evaluate the current corrosion activity state of the steel reinforcement inside the concrete cover.

[0049] Shear key body state detection. To directly obtain the working state of the shear key, various detection means can be used. For example, an industrial endoscope or a high-definition camera device is used to observe the appearance of the shear key by extending into the joint through a reserved hole or a newly opened inspection hole, and record whether there are obvious crushing, misplacement or surface corrosion phenomena. Preferably, ultrasonic flaw detection technology can be used, which principle is that ultrasonic beams are emitted on one side of the shear key and received on the other side or the same side, and by analyzing the propagation time, amplitude attenuation and reflected waveform of the ultrasonic signal, it is judged whether there are cracks, inclusions and other discontinuous defects inside the shear key. In order to obtain the actual stress data of the shear key under dynamic traffic load, resistance strain gauges can be attached to the key stress parts of the shear key and connected to a dynamic data acquisition system to record and analyze the stress-time history data when the vehicle passes.

[0050] Structure deformation measurement. Using high-precision level meters and total station instruments and other geodetic surveying equipment, the structure monitoring points arranged on the diseased pipe joint and its adjacent pipe joints are periodically re-measured in coordinates and elevations. Through this measurement, the accurate displacement and settlement rate of the structure in the vertical and horizontal directions can be obtained, providing basic data for deformation analysis.

[0051] After the above data collection and site investigation are completed, the comprehensive evaluation stage is entered. This stage is a process of systematically analyzing and integrating all the information obtained.

[0052] Specifically, the various data obtained from the site investigation and measurement, including structure deformation measured values, crack width measured values, shear key stress measured values, etc., are compared with the design allowable limits specified in the original design drawings and related technical specifications.

[0053] To further analyze the disease development trend, a local three-dimensional finite element model of the pipe joint containing the shear key can be established. The measured material performance parameters and deformation boundary conditions are input into the model, the stress distribution state inside the shear key and the relative deformation between the pipe joints under the current load and environmental action are simulated and calculated, and the long-term performance evolution trend can be predicted accordingly.

[0054] Finally, the overall safety state of the shear key is determined by comprehensively analyzing the historical data, the site test data, the limit value comparison results and the finite element model calculation conclusions. The disease degree of the shear key is divided, for example, it is determined whether it is in the state that the structure body has not occurred qualitative damage but the functional part is damaged, or in the state that the structure has occurred crushing, internal steel bar serious corrosion and other qualitative damage and the function is basically failed. The determination conclusion will be the direct technical basis for selecting the reinforcement repair method or the replacement repair method in step a.

[0055] b. Foundation treatment steps: Foundation treatment is carried out on the parts of the immersed tunnel with uneven deformation in order to improve the foundation density and adjust the uneven deformation;

[0056] In this embodiment, after completing the shear key safety assessment in step a and before performing the shear key repair in step S3, step b, namely the foundation treatment, is performed. The purpose of this step is to address the external factors that cause or aggravate shear key defects, namely the uneven settlement of the immersed tunnel caused by an unstable foundation, so as to provide a stable structural foundation for subsequent shear key repair work.

[0057] The initiation of this foundation treatment step is based on the results of the on-site investigation and measurement in step a. Specifically, when methods such as ground-penetrating radar detection in step a reveal areas of voids, cavities, or poorly filled areas beneath the immersed tunnel floor slab, it indicates that this step is necessary.

[0058] This step is specifically achieved by bottom grouting at locations where uneven deformation or foundation defects have been identified. This grouting operation aims to fill foundation cavities, improve the density and overall stiffness of the foundation soil, thereby adjusting existing uneven deformation and controlling subsequent differential settlement.

[0059] The specific execution method for this step is as follows:

[0060] First, a grouting construction plan is developed. This plan is based on the foundation detection data obtained in step a. The location, extent, and size of the voided areas marked on the ground-penetrating radar profile are converted into a specific grouting hole layout plan. This layout plan clearly defines the coordinates, drilling depth, and installation requirements of each grouting hole. Preferably, the grouting holes can be arranged in a staggered or matrix pattern to ensure uniform grout diffusion.

[0061] Next, grouting is carried out. Drilling is performed according to the grouting plan. After drilling is completed, grouting pipes are installed in the holes. Subsequently, a pre-prepared grout is injected into the target formation using a high-pressure grouting pump. The grout used can be a cement-based grout, or, depending on the formation conditions, a chemical-based grout with better permeability and setting time.

[0062] During the grouting process, synchronous monitoring is implemented. The purpose of this work is to ensure the grouting effect and prevent secondary damage to the tunnel structure. Monitoring includes: real-time recording of grouting pressure and the volume of grout injected; stopping or adjusting grouting operations when the pressure reaches a preset threshold or the grout volume reaches the designed volume; and simultaneously, using a high-precision level or static leveling system inside the immersed tunnel to monitor the elevation of the tunnel floor directly above the grouting area in real time, in order to control the uplift of the tunnel sections within the allowable range.

[0063] After the grouting operation is completed, the treatment effect is verified. Preferably, after the slurry reaches the designed strength, the grouting area is scanned again by the geological radar in the same way as in step a. By comparing the detection images before and after grouting, it is confirmed that the void area of the base has been effectively filled and the base density has been improved.

[0064] By performing the above base treatment steps, the foundation of the immersed tunnel can be effectively reinforced, creating a stable and reliable external condition for the shear key reinforcement or replacement repair operation in step c, to ensure the long-term effectiveness of the repair work.

[0065] c. Repair step: according to the results of the evaluation step, one of the following methods is selected to repair the shear key:

[0066] c1. When the shear key structure is not damaged, the reinforcement method is used for repair;

[0067] c2. When the shear key structure has been damaged, the replacement method is used for repair, which includes: first, transforming the original horizontal shear key of the immersed tunnel bottom plate into a temporary shear structure with both horizontal and vertical shear resistance, and then replacing the vertical shear key of the side wall using the vertical temporary constraint provided by the temporary shear structure;

[0068] In this embodiment, after the base treatment of step b is completed, step c, i.e. shear key repair, is performed. This step is the core execution link of the technical solution of the present application, and its specific implementation method depends on the damage degree of the shear key determined by the evaluation step a. This step provides two repair methods: reinforcement repair method and replacement repair method.

[0069] Reinforcement repair method

[0070] When the evaluation conclusion of step a determines that the shear key structure has not been damaged, but its constraint function has been damaged due to pipe joint deformation, etc., this reinforcement repair method is used. The purpose of this method is to restore or enhance the vertical shear resistance of the pipe joint under the condition of not removing the original shear key by adding external components.

[0071] In this embodiment, this reinforcement method is implemented by installing an Ω-shaped steel plate. The Ω-shaped steel plate is a component with a specific cross-sectional geometry. Its cross-sectional shape gives it specific mechanical properties: it has high bending stiffness and shear resistance in the direction perpendicular to the plane of the steel plate (i.e. the vertical direction of the tunnel); while in the direction parallel to the plane of the steel plate (i.e. the longitudinal direction of the tunnel), due to the presence of the bending section, it has low axial stiffness, allowing the pipe joint to have certain longitudinal expansion and deformation. The purpose of selecting this component is to effectively constrain the relative vertical displacement between pipe joints, while not introducing excessive longitudinal temperature stress or creep constraint stress to the tunnel structure.

[0072] The specific construction process of the Ω-shaped steel plate reinforcement is as follows:

[0073] First, the concrete surface of the side wall on both sides of the pipe joint to be installed with the steel plate is treated, for example, polished flat, to ensure that the steel plate can be closely attached to the concrete.

[0074] Subsequently, the Ω-shaped steel plate that has been pre-processed is hoisted into position. The width of the bent section of the steel plate is designed to match the actual width of the pipe joint joint. The straight sections on both sides of the steel plate are installed in the pre-buried clamping slots on both sides of the pipe joint.

[0075] The straight section of the Ω-shaped steel plate is connected with the clamping slot buried in the immersed tube section side wall using high-strength T-shaped steel plates. The installation of the connection between the high-strength steel plate of the straight section and the side wall clamping slot is as follows: first, grooves are opened at both ends of the side wall, and the groove size needs to meet the steel structure clamping slot installation. The steel structure clamping slot is connected to the side wall wall through the anchor bar. After the side wall clamping slot is installed, the T-shaped steel plate of the straight section is inserted into the clamping slot for connection, and the end of the side wall can be strengthened by steel plate welding.

[0076] The sizes and specifications of the connecting components such as the Ω-shaped steel plate, the straight section T-shaped steel plate, the clamping slot steel, and the anchor bar need to be determined based on the calculated vertical shear force shared by the shear force to be reinforced. The design shear capacity of the connecting components needs to be higher than the actual bearing capacity, and the size of the buried clamping slot and anchor bar needs to meet the anchoring requirements.

[0077] After the reinforcement work is completed, the exposed metal components such as the Ω-shaped steel plate and the anchor bolt are treated with a systematic corrosion and fireproof coating to ensure their long-term durability in the tunnel operating environment.

[0078] Replacement repair method

[0079] When the evaluation conclusion of step a determines that the shear key has been crushed, the internal steel bars have been severely corroded, and other qualitative damage, and the structure has been unable to continue to be used safely, this replacement repair method is used.

[0080] The core technology of this method is to provide temporary vertical restraint for the pipe joint during the process of removing and replacing the failed side wall vertical shear key, to prevent the pipe joint from being dislocated after the old shear key is removed. In this embodiment, the original horizontal shear key of the immersed tube tunnel floor is first modified to temporarily have vertical shear resistance, to solve the above technical problem.

[0081] Another important feature of this replacement repair method is that all removal and new construction work is carried out in blocks and parts. The purpose of this implementation method is to maintain the traffic capacity of the tunnel during the repair work, and not to completely interrupt the operation function of the tunnel.

[0082] The specific implementation steps of the replacement repair method are as follows:

[0083] Firstly, the bottom plate shear key is modified. The purpose of this step is to build a temporary structure with horizontal and vertical shear resistance at the bottom plate. The structure adopts a concave-convex step connection form. Specifically, at the position of the original horizontal shear key, the upper step structure and the lower step structure connected with the pipe sections at both ends are formed by block removal and pouring. The upper and lower step structures overlap in the vertical direction and mesh in the horizontal direction. The working principle is that when the pipe sections have relative horizontal displacement, the side surfaces of the steps contact and transfer horizontal shear; when there is relative vertical displacement, the top and bottom surfaces of the steps contact and transfer vertical shear. Through this structure, the modified bottom plate shear key can simultaneously bear horizontal and vertical shear loads. The geometric size of the step structure needs to be determined through calculation to ensure that the vertical and horizontal shear resistance provided by the step structure meets the stress requirements of the temporary constraint stage. The gap between the upper and lower steps is preferably filled with flexible materials such as rubber strips to adapt to the joint deformation.

[0084] The modification process of the above-mentioned bottom plate shear key strictly follows the principles of block construction and site construction. For example, the modification of the areas on both sides of the road can be constructed first, and after the design strength is reached, the middle area can be constructed. This process ensures that at least one lane is passable through traffic diversion. The temporary structure can be cast-in-place concrete, or precast concrete or steel structure to shorten the construction period.

[0085] Secondly, after confirming that the concave-convex step type temporary shear structure of the bottom plate has formed effective constraint and reached the design strength, the failed side wall vertical shear key is removed.

[0086] After the removal is completed, a new shear key is replaced at the original position. The new shear key can be a reinforced concrete shear key poured according to the design requirements, or a precast steel shear key.

[0087] Finally, after the new side wall vertical shear key reaches the design strength and can fully bear the vertical shear, the concave-convex step type temporary shear structure of the bottom plate can be selectively replaced and restored to the original design shear key with only horizontal shear resistance through block construction and site construction according to the long-term functional requirements of the tunnel.

[0088] d. Acceptance step: safety evaluation of the repaired shear key to confirm the repair results.

[0089] Preferably, the evaluation step a specifically includes:

[0090] Collecting original design data, geological data and operation monitoring data of immersed tube tunnel; and conducting field investigation to obtain data of base compactness, structural cracks, and damage degree and stress state of shear key; comparing the obtained data with design deformation limit value to comprehensively evaluate safety degree of shear key;

[0091] In the embodiment, after the shear key repair work entity construction in step c is completed, step d, i.e., evaluating repair results, is performed. This step aims to technically verify effectiveness of the repair work implemented in step c through a series of objective detection and evaluation, and to provide decision basis for whether to enter the next final step.

[0092] The evaluating repair results step is specifically implemented through the following work:

[0093] First, stress monitoring is performed on the repaired shear key structure. The purpose of this monitoring is to directly obtain working state data of the newly set or reinforced shear key under actual operation load to verify whether it bears and transfers shear force as expected by design. In specific implementation, sensors can be arranged at key positions of the repaired structure. For example, in repair using the Ω-shaped steel plate reinforcement method, resistance strain gauges can be pasted at key cross sections of the Ω-shaped steel plate; in repair using the replacement repair method, strain gauges can be arranged at key load transfer positions of the newly replaced shear key body or the concave-convex stepped temporary structure of the base plate. Through continuous collection and recording of stress-time history data of these positions when vehicles pass by in a predetermined observation period, the measured stress peak value is compared with the material allowable stress value obtained by structure design calculation to determine whether the working stress of the repaired structure is within a safe range.

[0094] Second, deformation monitoring is performed on the repaired pipe joint structure. The purpose of this monitoring is to evaluate overall stability of the tunnel structure after the base treatment in step b and the shear key repair in step c, and in particular to verify whether the original uneven settlement disease has been effectively controlled. In specific implementation, high-precision level meters, total stations and other measuring equipment are used to periodically re-measure elevations and three-dimensional coordinates of structural deformation monitoring points arranged on the repaired pipe joint and adjacent pipe joints. The deformation data obtained by re-measurement is compared and analyzed with historical data before repair and during repair to determine whether the structural deformation rate has tended to be stable, and whether the cumulative deformation amount is controlled within the limit value allowed by design specification.

[0095] Again, durability assessment of the materials used for repair is performed. The purpose of this assessment is to verify whether the performance of the new materials used in the repair project (such as high-strength concrete, steel, chemical anchoring agent, anti-corrosion coating, etc.) meets the design and long-term operation requirements. In practice, the rebound method or ultrasonic method can be used to detect the strength of the newly poured concrete structure; for Ω-shaped steel plates or newly replaced steel shear keys, a coating thickness gauge can be used to detect whether the anti-corrosion coating thickness meets the standard, and the appearance is checked to confirm that there is no early signs of rust. Through these detections, a basis for evaluating the long-term performance of the repair project is provided.

[0096] Finally, comprehensive evaluation is performed. The technical documents such as the above-mentioned structural stress monitoring report, deformation monitoring report and material durability assessment results are collected to form a complete repair achievement evaluation data. This data will be submitted to a review group composed of technical experts in the relevant field for review. The expert group will make a comprehensive evaluation of the overall effect of the repair project based on relevant technical standards, design documents and all objective data obtained during this evaluation, and issue a formal review conclusion to determine whether the repair achievement is qualified or unqualified.

[0097] This step includes a conditional judgment process: if the review conclusion is qualified, it means that the repair work has achieved the expected technical target and can be handed over to the next step; if the review conclusion is unqualified, it means that there are unresolved technical problems or the expected effect has not been achieved in the repair work, at which time the process must be returned to step c, and additional repair or re-planning and re-implementation of repair work must be performed for the problems found in the assessment until the subsequent evaluation results are qualified.

[0098] Although embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and alterations can be made thereto without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for repairing shear key defects in an operating immersed tunnel, characterized in that, The method comprises the following steps: a. an evaluation step: safety evaluation of the shear key of the operating immersed tunnel to determine the damage degree thereof; b. a base treatment step: base treatment is performed on the part of the immersed tunnel where uneven deformation exists to improve the base density and adjust the uneven deformation; c. a repair step: according to the result of the evaluation step, the shear key is repaired in one of the following modes: c1. when the shear key structure is not damaged, reinforcement is adopted for repair; c2. when the shear key structure is damaged, replacement is adopted for repair, which comprises: first, the original horizontal shear key of the immersed tunnel bottom plate is transformed into a temporary shear structure with both horizontal and vertical shear resistance, then the vertical temporary constraint provided by the temporary shear structure is used to replace the vertical shear key of the side wall, and after the replacement is completed, the bottom plate shear key is restored. d. an acceptance step: safety evaluation of the repaired shear key to confirm the repair result.

2. A method for repairing defects in shear keys of an immersed tunnel according to claim 1, characterized in that, The evaluation step a specifically comprises: Original design data, geological data and operation monitoring data of the immersed tunnel are collected, and field investigation is performed to obtain data of base density, structural cracks, damage degree and stress state of the shear key; the obtained data are compared with the design deformation limit value, so as to comprehensively evaluate the safety degree of the shear key.

3. A method for repairing shear key defects in an immersed tunnel according to claim 2, wherein, The reinforcement mode c1 specifically adopts Ω-shaped steel plate for reinforcement, which comprises: Ω-shaped steel plate is adopted, and the flat section of the Ω-shaped steel plate is connected to the side wall at both ends of the immersed joint in a clamping groove mode to provide vertical shear resistance by the Ω-shaped steel plate.

4. The method of claim 1, wherein the method is suitable for repairing a shear key defect of an immersed tunnel. The width of the bent section of the Ω-shaped steel plate is adapted to the spacing of the joint seam of the pipe joint, and the size and strength of the clamping groove connection between the flat section and the side wall at both ends of the immersed joint are determined according to the shear strength requirement.

5. A method for repairing shear key defects in an immersed tunnel according to claim 4, wherein, In the replacement mode c2, the method of transforming the original horizontal shear key of the bottom plate into a temporary shear structure specifically comprises: A new shear key structure with concave-convex stepped connection is arranged at the position of the original horizontal shear key of the bottom plate, which realizes the functions of horizontal and vertical shear transmission by the engagement of the upper and lower steps.

6. A method for repairing shear key defects in immersed tunnel according to claim 1, wherein, All the demolition and construction operations in the replacement mode c2 are implemented in a block-by-block and part-by-part manner to ensure that the traffic of the tunnel is not interrupted during the repair process.

7. The method of claim 1, wherein the method is suitable for repairing shear key defects in immersed tube tunnels. The acceptance step d specifically comprises: Force monitoring, deformation monitoring and material durability detection are performed on the repaired shear key structure, and expert review and evaluation are performed, and if the evaluation is unqualified, the repair step c is repeated.

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